feat: add find_orphaned_wires schematic analysis tool

Detects wire segments with at least one dangling endpoint — an endpoint
not connected to a component pin, net label, or another wire.  These
cause ERC 'wire end unconnected' violations and are a common symptom of
incomplete routing or stray stub wires.

Algorithm uses exact KiCad IU (10 000 IU/mm) coordinate matching,
consistent with wire_connectivity.py:
  1. Build an endpoint-frequency map for all wires (IU precision)
  2. Collect anchored IU points: component pins (via PinLocator),
     net labels / global_labels, power symbol pins
     (via _parse_virtual_connections)
  3. An endpoint is dangling when it is touched by exactly one wire AND
     is not an anchored point; the containing wire is reported

Does not require the KiCad UI to be running.

Changes:
  python/commands/schematic_analysis.py — find_orphaned_wires() function
  python/kicad_interface.py             — handler + route registration
  python/schemas/tool_schemas.py        — MCP schema entry
  src/tools/schematic.ts                — TypeScript server.tool() call
  tests/test_schematic_analysis.py      — 7 integration tests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

python/kicad_interface.py

@@ -403,6 +403,7 @@ class KiCADInterface:
             "find_overlapping_elements": self._handle_find_overlapping_elements,
             "get_elements_in_region": self._handle_get_elements_in_region,
             "find_wires_crossing_symbols": self._handle_find_wires_crossing_symbols,
+            "find_orphaned_wires": self._handle_find_orphaned_wires,
             "import_svg_logo": self._handle_import_svg_logo,
             # UI/Process management commands
             "check_kicad_ui": self._handle_check_kicad_ui,
@@ -2936,6 +2937,31 @@ class KiCADInterface:
             logger.error(traceback.format_exc())
             return {"success": False, "message": str(e)}
 
+    def _handle_find_orphaned_wires(self, params: Dict[str, Any]) -> Dict[str, Any]:
+        """Find wire segments with at least one dangling (unconnected) endpoint"""
+        logger.info("Finding orphaned wires in schematic")
+        try:
+            from pathlib import Path
+
+            from commands.schematic_analysis import find_orphaned_wires
+
+            schematic_path = params.get("schematicPath")
+            if not schematic_path:
+                return {"success": False, "message": "schematicPath is required"}
+
+            result = find_orphaned_wires(Path(schematic_path))
+            return {
+                "success": True,
+                **result,
+                "message": f"Found {result['count']} orphaned wire(s)",
+            }
+        except Exception as e:
+            logger.error(f"Error finding orphaned wires: {e}")
+            import traceback
+
+            logger.error(traceback.format_exc())
+            return {"success": False, "message": str(e)}
+
     def _handle_import_svg_logo(self, params: Dict[str, Any]) -> Dict[str, Any]:
         """Import an SVG file as PCB graphic polygons on the silkscreen"""
         logger.info("Importing SVG logo into PCB")